Method of preparing iron for castings.



UNITED STATES PATENT OFFICE.

WILLIAM G. KEANZ, OF SHARON, PENNSYLVANIA, ASSIGNOB. TO THE NATIONALMALLEABLE CASTINGS COMPANY, OF CLEVELAND, OHIO, A CORPORATION 01 OHIO.

1,132,661, Specification of Letters Patent.

No Drawing. Application filed April 17, 1911.

To all whom it may concern Be it known that I, WILLIAM G. KnAnz, ofSharon, Mercer county, Pennsylvania, have invented a new and usefulMethod of Preparing Iron for Castings, of which the following is a full,clear, and exact description. i

My invention relates to the treatment of iron intended to be made intocastings which may be malleableized or otherwisetreated; and is designedto overcome the dlfiiculties resulting from the presence of relativelyhigh sulfur in the castings. The presence of considerable percentage ofsulfur (.06.10) causes a considerable proportion of the castings tocrack so that in ordinary malleable work the loss by cracking is animportant item of expense. For this reason it has been customary toemploy for malleable working pig iron low in sulfur and consequently ofrelatively high cost.

My invention is designed to utilize any grade of iron or scrapirrespective of ts sulfur content, thus enablin low grade and low costmaterial to be use since by my process the sulfur is reduced to a lowcontent so that the liability to crack from this cause is greatlyreduced or eliminated.

In carrying out my method, the pig iron or scrap, or both, which may bebig 111 sulfur and of relatively low cost, are melted at a relativelylow heatin any suitable furnace, such as a cupola, open hearth furnace,or the air furnace now commonly used 1n malleable iron work. In thismelting, for which I prefer to use the cupola, it is pract cally imossible to remove sulfur. This premelte material is then charged inmolten condition into an electric furnace of any desirable t e, such asthe electrode type (Heroult or irod for example), or of t e inductiontype. In this electric furnace, lime is added either in raw or burntform, preferably the latter, and the temperature raised to remove thesulfur, referabl in connection with carbon ad itions. prefer to test thepremelted material for carbon, and to add sufiicient carbon in theelectric furnace so that after the oxide are practically eliminated, thecarbon will react with the lime and form calcium carbid. The formationof this carbid enables me to test for elimination of oxids, and when thetemperature of the metal is relatively high the sulfur is reduced to asmall content or practically METHOD OF PREPARING IRON FOB CASTINGS.

Patented Mar. 23, 1915.

Serial No. 621,723.

eliminated. If the carbon is low in the melted material, I alsopreferably add suificient carbon in the electric furnace to raise thecarbon content to about the per cent. desired in the product.

After the sulfur and oxids are substan tially removed, I can make anydesired advditions, such as carbon, to give the carbon content desired,or an alloying metal, if desired, such as titanium or vanadium. As theoxids have been removed there will be practically no loss in theseadditions. The metal which is white iron is then tapered out and takento the molds, after which the castings are malleableized in any desiredmanner common in this art. My product contains from 11} to three percent. of carbon, .5 to 1 per cent. of silicon, sulfur .05 or under, andmanganese under .5.

The advantages of my new process will be apparent to those skilled inthe making of malleable iron castings, since the troubles arising fromsulfur are practically done away with; and a better grade of iron formalleableizing or other purposes obtained from the poorest and cheapestgrade of material, than is now obtained from relatively high grade pigiron. Changes may be made in the apparatus employed in carrying out myinvention; other ways of testing for elimination of oxids may be used,than the calcium carbid test above recited; carbon may or may not beadded, when feeding into the electric furnace, or after the treatmenttherein; alloying materials may or may not be added; and ot erchangesmay be made in the process without departing from my invention.

I am aware that the electric furnace has been used as a finishing stepin the manufacture of steel by the open hearth or Bessemer process; butsuch steel processes are entirely dissimilar from mine, since in suchrocesses the carbon is reduced to a relatively low point orsubstantially eliminated, tlius giving reduction of phosphorous and sulfur in the oxidizing step prior to using the electric furnace; whereinmy processe -the carbon must be kept high throughout the process, theelectric furnace enabling me to Substantially eliminate the sulfur whilekeeping high carlion.

I claim:

1. The method of preparing iron for castings. consisting in treatlngmolten iron relatively high in carbon, by feeding molteniron into anelectric furnace, raising its temperature and treating it with lime inthe electric furnace to reduce the sulfur content, While maintaining arelatively high carbon content therein, substantially as described.

2. The method of preparing iron for castings, consisting in treating lowgrade molten iron high in carbon and sulfur, by feeding the molten ironstill high in carbon and sulfur into an electric furnace, raising itstemperature and treating it therein With lime which forms a basic slagto receive the sulfur content, while maintaining relatively high carboncontent, substantially as described.

3. The method of preparing iron for castings, consisting in treating lowgrade molten iron high in carbon and sulfur, feeding the molten ironstill high in carbon and sulfur into an electric furnace, raising itstemperature and treating it therein With lime which forms a basic slagto receive the sulfur content, While maintaining a relatively highcarbon content, and adding carbon to the molten iron in the electricfurnace, substarr tially as described.

4. The method of preparing iron for eastings, consisting in treatingmolten iron high in carbon, by feeding the molten iron still high incarbon into an electric furnace, raising its temperature therein,treating it With lime to remove the sulfur and continuing the treatmentWhile maintaining a relatively high carbon content until oxids aresubstantially removed, substantially as described.

5. The method of preparing iron for castin s, consisting in treatinmolten iron high in carbon and sulfur, by eeding the molten iron stillhigh in carbon and sulfur into an electric furnace, raising itstemperature therein, treating it with lime to remove the sulfur,continuing the treatment until calcium carbid is formed showing theelimination of oxids from the metal, and then making additions of carbonand tapping out, substantially as described.

6. The method of preparing iron for castings, consisting in treatingmolten iron high in carbon and sulfur, by feeding the molten iron stillhigh in carbon and sulfur into an electric furnace, raising itstemperature, treating it With lime therein, removing the sulfur untilthe oxide are substantially removed, and then adding carbon and tappingout, substantially as described.

7. The method of preparing iron for castings, which consists in treatingmolten material high in carbon, by feeding the molten material high incarbon into an electric furnace, raising its temperature and treating ittherein until the oxids are substantially removed While maintaining arelatively high carbon content, and then making additions and tappingout, substantially as described.

8. In the making of high grade pig iron the process Which consists inintroducing into an electric furnace iron in a molten conditioncontaining sulfur, maintaining it molten therein in a non-oxidizingatmosphere and under nonoxidizing conditions and treating it basicallytherein to remove sulfur.

9. In the treatment of iron, the process which consists in introducinginto an electric furnace iron in a molten condition containing sulfur;maintaining it molten therein in a non-oxidizing atmosphere and undernon-oxidizing conditions; and treating it basicallyto remove the sulfur.

In testimony whereof, I have hereunto set my hand.

W; G. BAILEY, J. H. SLAWSON.

It is hereby certified that in Letters Patent No. 1,132,661, grantedMarch 23, 1915, upon the application of William G. Kranzpof Sharon,Pennsylvania, for an improvement in Methods of Preparing Iron forCastings, errors appear in the printed specification requiringcorrection as follows: Page 1, line 68, for the word tapered readtapped; same page, line 70, for the word desired read desirable;

and that the said Letters Patent should be read with these correctionstherein that the same may conform to the record ofthe case in the Patent()flice.

Signed and sealed this 20th day of April, A. D., 1915.

[BELL] J. T. NEWTON,

Acting Commissioner of Patents;

